FAQ

General Frequently Asked Questions

Table of Contents

Running Jobs

Running Jobs

How do I forward X11 traffic (for example, from TotalView) from batch jobs?

To use TotalView or other X11 applications within a batch job, the system must be able to direct the X11 traffic back to your workstation. To do this, you should first connect to ewok.ccs.ornl.gov with X11 forwarding enabled. This can be done as a configuration setting in your ssh client or can be done by adding -X to the ssh command line (ssh -X ewok.ccs.ornl.gov). Once logged on to ewok, you can run a command such as xterm or xclock to verify X11 forwarding is working. Once X11 forwarding is in place, you must tell PBS that you want to use X11 forwarding in your job. This is done with the -X option to qsub. So, to submit a job for a 64 processor debug session, you might use 

qsub -I -X -lnodes=32:ppn=2,walltime=1:00:00 -A ABC123

where ABC123 is your Project ID.

How do I launch TotalView?

The procedure for launching TotalView on ewok is slightly different than the procedure on other systems. To use TotalView on ewok, first load the totalview module: 

module load totalview

This is important, because it sets variables that are required under ewok’s environment. It also sets up “mpirun_tv” as an alias (under csh/tcsh) or a function (under other shells).

After loading the module, simply launch your MPI job using mpirun_tv as the job launcher: 

mpirun_tv -np 16 ./a.out

NOTE: You should not provide a hostlist or the “-tv” option to mpirun_tv. These are set up as part of the alias/function. Additionally, the executable to be debugged MUST be the last entry on the mpirun_tv command line.